So I'm having a hard time finding bm dresses. My bp varies from 5'1" 98 lbs to 5'8" 180 lbs.

What do I put them in to make them all feel beautiful and comfortable? Help!!!

I am a big fan on Jim Hjelm.  My wedding parties size vary as well and they all loved their designs. www.jlmcouture.com.  My girls are wearing style number 5935.

Bill Levkoff is the designer I am probably going to be going with....

That is tough. I'm thinking about letting them pick different styles just all in the same color. 

I think your best bet would be to let them pick out different styles in the same color and fabric.

I was going to pick the material and color and they were going to pick whatever dress they wanted, and it turned out they all LOVED the same one...haha.  I would give them that option.  I choose Jim Hjelm, but Davids Bridal would work for you too.  They have so many options.

I was in my friend's wedding in the summer.  We were 3 girls with varying body types.  The bride told us we could pick whatever styles we likes, just keep them tea length and of the same colour.  We all ended up liking the same style and it looks great on all of us!  Don't worry about it too much... just go shopping and see what you come up with :)

I am having all my girls pick knee length blak dresses. I'm letting them choose one that they like and feel comfortable in (just asking that they run their options by me before choosing). I think they will all feel more comfortable this way and they will all be able to wear them again! :)

I have a bunch of BMs - 9 to be exact! - and I am going with the similar style/same fabric idea... I gave them the choice of any of these three dresses (in the same color) and they all picked the dress that best fits their style/is most flattering on them. The fabric is very forgiving, so the dresses look great on all of them. I am so happy with what I picked out (and so are they!) -- good luck!
http://www.dessy.com/dresses/lelarose/lr100/

http://www.dessy.com/dresses/lelarose/lr101/

http://www.dessy.com/dresses/lelarose/lr102/